<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="com.css"/>
    <style>
        #i1{font-size:50px;}
    </style>

<div class="c2">
    <div></div>
    <div>
        <p>
            <a class="c3">a</a>
        </p>
    </div>
</div>
<div class="c3"></div>
</head>
<body>
    <h1 id="i1">哈哈哈</h1>
    <div style="background-color: black;color: white">白底黑字</div>
    <div>哈哈</div>
</body>
</html>